With no new Ebola cases in five days, US authorities were cautious but hopeful Monday that the virus has been contained in the United States after a flawed response revealed shortcomings in the system.
The fiancee of a Liberian man who died of Ebola earlier this month in Dallas, Texas, was among nearly 50 people who emerged from three weeks of quarantine without any signs of illness from exposure to the virus that has killed more than 4,500 in West Africa since the beginning of this year.
About 100 more people, most of them health care workers, are being tracked in Texas after coming in contact with the first patient diagnosed in the United States in late September.
Still, officials said it was reassuring that no new infections emerged in recent days.
"We are breathing a little bit easier, but we are still holding our breath," said Dallas Mayor Mike Rawlings.
Two US women were infected during the care of Liberian patient Thomas Eric Duncan. Both were nurses in the intensive care unit -- Nina Pham, whose infection was announced October 12, and her colleague Amber Vinson three days later.
Ebola is spread though close contact with vomit, blood, diarrhea or other bodily fluids. Most people get sick within eight to 10 days of exposure, and health care workers are particularly at risk.
Officials have sought to contain panic over the potential spread of Ebola, as fears mounted in the United States and a rash of suspected cases turned out to be nothing more than common illnesses.
"In the United States, two people have gotten infected with Ebola. Two. Both of them were taking care of a desperately ill patient in a risky situation," said Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases, during a forum at Washington's Newseum.
"You have to distinguish the two nurses -- who were the only two people who were taking care of patients who got infected -- from the risk to the general public who aren't anywhere near an Ebola patient, much less a very sick Ebola patient."
Pham is in fair condition, and Fauci declined to speculate on whether she would make a full recovery.
"She still is a bit knocked out," Fauci said.
"When you get an infection as serious as Ebola it is very, very draining on you."
Vinson's family said in a statement Sunday they "remain intensely prayerful and optimistic about Amber's condition and of the treatment she is currently receiving" at Emory University Healthcare, in Atlanta Georgia, but gave no details on the state of her health.
Texas Health Presbyterian Hospital in Dallas, which initially sent Duncan away when he sought care for pain and a fever, apologized Sunday for its handling of the case.
"As an institution, we made mistakes in handling this very difficult challenge," the hospital said in Sunday's Dallas Morning News.
"The fact that Mr Duncan had traveled to Africa was not communicated effectively among the care team, though it was in his medical chart," the hospital said in its letter, which was signed by Texas Health CEO Barclay Berdan.
"We did not correctly diagnose his symptoms as those of Ebola. For this, we are deeply sorry."
Jesse Goodman, a doctor and public health expert at Georgetown University, said the United States was learning from the intially flawed response.
"I do think events indicate how important it is to probably be over cautious rather than over confident," said Goodman at the Newseum event.
"And how when you are dealing with a new problem in a very complicated environment like the US healthcare system, you really need to -- if anything -- be over clear, over trained and over cautious."
Fauci added that the global Ebola epidemic was far from ending in West Africa, and said all nations need to pour resources into ending the spread of the disease there.
"Right now I don't think we can predict when this epidemic is going to be over. When you look at it, it is still escalating rather than declining."